Image Title:Exploration ImageryDescription:Artist's concept of possible exploration programsS86-25375 (1986) --- (Artist's concept of possible exploration programs.)On Phobos, the innermost moon of Mars and likely location for extraterrestrial resources, a mobile propellant-production plant lumbers across the irregular surface. Using a nuclear reactor the large tower melts into the surface, generating steam which is converted into liquid hydrogen and liquid oxygen.